Hello folks,

Got my Fiat a couple of years ago from a friend and have been working on it part time ever since.
Photos dump below and link to Imgur album - https://imgur.com/a/xDmdeSA
Also a more detailed version is on my Instagram - https://www.instagram.com/stories/highl ... 515486486/

Here is the list of the things that i did to it so far:

• 1. Welded the giant hole that was left by the donut exploding and driveshaft coming in the salon for a visit
  2. Stripped all old sound deadening replaced it with new stuff
  3. New carpets
  4. Sewn and reupholstered the seats myself
  5. Rebuild the 5sp transmission - twice. honestly just for fun, sold the second one
  6. Rebuild the driveshaft, new u-joints, new center bearing
  7. Front, rear rotors and pads
  8. New control arms, bearings and ball joints in the front
  9. Refurbished the steering dampener, ordering a new seal and just press fitting it in.
  10. New springs and shocks.
  11. Replaced the wheels
  12. Removed the old bumpers
  13. Put in some fresh LED headlights
  14. New radiator

A few months ago i was driving and suddenly lost 90% of my power. Barely limped home to find that my ignition coil and computronix are toast. Decided that it was a good time to pull the engine and do a full rebuild. Stripped it down and now wondering what to do next as i'm a bit out of my expertise here.

Here is my plan:

• 1. I would like to go with increased compression - up to 10.8:1. Get the pistons from AutoRicambi (https://autoricambi.us/piston-set-1756- ... ion-ratio/). Go 1.0mm oversized.
  2. Get the aluminum crankshaft pulley - https://autoricambi.us/aluminum-crank-p ... 8-to-1985/
  3. Bring the pistons and block for bore and hone to a local machine shop
  4. Bring the pulley, crankshaft, flywheel and pressure plate to a local machine shop for balancing and polishing (hopefully don't need to grind anything)
  5. Start putting it back together.

Here are my questions, lets number them so its easier to answer:

• 1. What camshaft do i need for this higher CR?
  2. Can i just use the standard head gasket?
  4. Do i need to replace the freeze plugs? (i'm in California, never will drive it in the snow)
  5. Can i reuse the head bolts?
  6. My exhaust manifold is cracked. Should i get a good used one or just have it welded by someone?
  7. Do i need to resurface my head before putting it back together?
  8. Not actually sure if i need to do anything with valve or the head itself.

My plan until a few days ago was to convert to a Speeduino, but alas just like everyone before me said - no time to mess around with it. I need to finish this project.

Since day 1 - i've kept a meticulous log of all the expenses that this project has incurred on our family If there is interest i can post it on Googly sheets.

Any other advice is much appreciated - this is my first time rebuilding an engine.

Nice work so far, and thanks for sharing! I'm not an expert on performance builds, but I've rebuilt several engines (just keeping them stock). A few answers to your list below. Just curious, where in CA are you? I'm east of San Francisco about an hour.

-Bryan

4. Do i need to replace the freeze plugs? Unless they are leaking or corroded, I'd leave them be. My understanding is that they were more used for the factory casting process than as a "safety valve" should be block freeze. The machine shop should be able to provide advice on whether they should be changed. Taking them out does allow a better cleaning of the inside of the block.

5. Can i reuse the head bolts? I do, but I also check to make sure that none have stretched or have damaged threads. However, with a 10.8 CR, the money spent on new head bolts (or studs) might be a good investment.

6. My exhaust manifold is cracked. Should i get a good used one or just have it welded by someone? I think this would depend on where it is cracked. On the flange where it is attached to the head, or the flange that goes to the downpipe, or elsewhere? I think yours is cast iron, which is hard to weld, but there are people who can do this. Likely not cheap, and a better option might simply be a good used manifold or a new one. With your performance build, you might consider headers and a performance exhaust system.

7 (and 2). Do i need to resurface my head before putting it back together? Yes. I wouldn't have the shop remove too much metal, but a light surface skim to prepare the head for a new gasket is a must. As for a specialty gasket (like MLS, or Multi-Layer Steel), it's probably a good idea with your higher CR.

8. Not actually sure if i need to do anything with valve or the head itself. There are many options here such as porting out the passageways, oversized valves, reshaping valves and guides, etc. At a minimum, I would have a good valve job done on the head, as well as a good cleaning. Sometimes the coolant entryways into the head corrode, so you could have these welded up. Again, much can be done, but a lot depends on how much $$$ you want to spend.

Hey Bryan,

I'm in San Jose!
4. I'll leave the plugs for the shop to decide.
5. I'll order a set of bolts.
6. Exhaust manifold is cast iron. I'm not sure if i can get the performance headers and still pass the draconian CA smog. For now, i'll be on a look out for a good used one - If anyone has one please ping me your details.
7. Thats what I thought - take a tiny bit off the top to get it ready for the new head gasket.
8. To be honest, I don't know what goes into a valve job yet - i'll make sure to educate myself.

fiat124pauk wrote:I'm in San Jose!

Great! Give me a holler sometime if you need a hand or some in-person advice. I'm retired, so my time is fairly free these days. San Jose is only about 45 minutes from where I am (south Livermore), but as you know, a lot depends on traffic.

I don't have a manifold for a 1980. The good news is that the original Fiat manifold wasn't too bad, and you might be able to find a shop that can fix it. Or just get a good used one as I mentioned.

-Bryan

Nice looking car and great pictures. Looks like you have done an awesome job so far.

The Fiat Twincam is a pretty simple engine to rebuild for the first time. I would recommend getting some books or studying online though.

What is your goal, purpose for the rebuild?

What piston were you looking at? I would advice against the 8mm dome piston in a 1800 - too much CR. The 1800 has a smaller chamber.

I would not do 1mm over size. I would go to the next smallest oversize and only if the bore does not clean up with a hone job. The few extra cc will do you nothing but will make the margin between bores very narrow and head gaskets hard to find.

Regarding the aluminum cam pulleys: The only reason to get them is if you need to adjust cam timing. This means meticulously degreeing the cams. Also, both the easily available adjustable pulleys have major problems with concentricity and fit. Not a simple bolt on. I have used both and spent a lot of time adjusting, fitting.

Regarding your questions:

1. Cam. It depends on what your goal is. Power?
2. I would recommend a MLS gasket. They are superior, but require a perfectly smooth head surface. You would want to tell the shop to surface the head as little as possible but for a mirror finish for MLS. If the head has been previously cut, the cutter can hit the hardened steel valve seat inserts and result in bad surface finish. Need to assess this at disassembly.
5. I'd replace the head bolts with the torx head bolt set.
8. I'd take the head apart. Seems like you are a capable mechanic. Examine valve guide wear. examine seats. Replace valve springs. At least resurface valve faces and lap seats. I did all the head work myself except for the resurfacing.

Below is a link to my misc rebuild pics:

https://photos.app.goo.gl/9Lxcty7LDyyDsTQv5

Hey nut124,

I forgot to mention that this is a 2.0L Fuel Injected 124 Spider.
I've looked through your photos and have a much better appreciation on the work involved!!!! Looks amazing what you have done with your engine!

The goal of the build was to get a bit more power out of the engine, since it is already out and apart. But the more i dig into it, the more it is going to cost.

If i go with 10.8:1 CR, i need to get different camshafts ($360), then i would need to get new adjustable cam pulleys ($200) plus messing around with milling the head.

At this point i'm heavily leaning towards getting the stock 8.8:1 pistons. Learning a bit more. I ordered a dial bore gauge, going to measure the cylinders first before doing anything.

I noticed that there is a lip on the cylinder, so if we dont need a bore, then i will have to recut that lip. Found this video - https://www.youtube.com/watch?v=hVnpsBbNcdQ

More updates next week when the gauge comes in.

fiat124pauk wrote:Hey nut124,

I forgot to mention that this is a 2.0L Fuel Injected 124 Spider.
I've looked through your photos and have a much better appreciation on the work involved!!!! Looks amazing what you have done with your engine!

The goal of the build was to get a bit more power out of the engine, since it is already out and apart. But the more i dig into it, the more it is going to cost.

If i go with 10.8:1 CR, i need to get different camshafts ($360), then i would need to get new adjustable cam pulleys ($200) plus messing around with milling the head.

At this point i'm heavily leaning towards getting the stock 8.8:1 pistons. Learning a bit more. I ordered a dial bore gauge, going to measure the cylinders first before doing anything.

I noticed that there is a lip on the cylinder, so if we dont need a bore, then i will have to recut that lip. Found this video - https://www.youtube.com/watch?v=hVnpsBbNcdQ

More updates next week when the gauge comes in.

Not sure what pistons you are considering. The 4mm dome ones should be ok.

You do not have to replace the cams just because you increase CR. It will run just fine with stock cams in proper adjustment.

Sometimes the lip in the bore is residue, deposit, and will clean up. If not, it will need to be bored. I'd leave all that and any bore measurement up to the machine shop. Measuring bore is not easy. Let the shop do it.

Regarding the the ridge reaming video; I'm a redneck mechanic myself, but that video is a bit far out for me. Perhaps if you are on a super tight budget.

If you manage to ream the ridge, then you'd want to flex hone the bores.

My last rebuild, we did not bore the block. It was just honed.

Nut, thanks for the pictures, and I'll have to study them some more. Documentation is one of my weak spots... I do the work but don't take the pictures.

I agree that if the ridge in the bore is not too extreme, it can either be honed out or just lightly sanded. I have also used a ball hone to "clean up" the bores and get them ready for new rings, with good results. The technique takes some practice to get used to, but the results are good.

I'm also of the opinion that you should never remove metal unless you absolutely have to. So, for me personally, I would only bore out a block if there is scoring or other damage in the walls. Different story if you're building a race engine where squeezing out every last HP is one of the primary factors, but for a street car, once you enlarge the bores you can't go back.

I know that there are machine shops that do exceptional work, but I also know how much work certain jobs take, roughly what the hourly wage of the shop is, and what they charged me. Sometimes it doesn't always add up. Maybe they are just good at what they do and don't take the time that I would, but maybe they are also doing things quickly. So I guess my point is that I have seen some really great work done by people in their garage, when they had the knowledge and the right tools and could take the time to set things up right, do a careful job, and clean up afterwards. Nut124's cutting of valve seats seems to be in this category.

That being said, if this is your first or second time rebuilding an engine, taking it to a good machine shop is likely the best approach.

-Bryan

my 0.02$ worth (likely overpriced) is that for a cheap engine refurbish i would:
hone the cylinders, and remove the lip
install new rings as a minimum, and only install new pistons if i was feeling rich
concentrate on the head with new valve guides and clean up the intake and exhaust passages and then as a minimum reseat the existing valves. I would install new valves with recut seats before i would buy new pistons.
then confirm the head is flat as well as the block
I think adjustable cam pulleys might well give you move performance increase than many other improvements.

At that point you have improved breathing, good compression and minimal investment
Then rework the exhaust to sound louder and you are done!

cheers
dinghyguy

Thanks everyone for the advice so far.

A few updates:
1. dropped off the block with a local machine shop, waiting for their verdict on the cylinder and crank measurements before i buy the cylinders and shaft bearings
2. mostly spent the time cleaning up parts and getting them ready for painting - nothing too exciting.

If you are going to have the block bored, or even honed, the shop will want the pistons there. The pistons have the bore dimension printed on them and the shop will want to measure the the pistons vs the bore.

Update:

1. Got a bunch of stuff purchased - 9.8:1 CR pistons, gaskets, 123 Ignition, new water pump kit, lots of small things
2. Had the machine shop bore, hone and clean the block for 0.04"+ pistons
3. Painted the block, pan and a few brackets.
4. Started the engine assembly.
Let me know if you see any issues!

Looking good! Just a few thoughts and you likely know all this:

- Make sure the two thrust washers are facing the correct way. The groove in them should face the shoulder of the crank, not the block. They are often installed backwards which leads to issues.

- Make sure the main bearing caps are installed in the right order (1,2,3,4,5) and facing in the right orientation. Same with the caps on the ends of the connecting rods. The numbers on the rod caps should match which rod they go with (and thus which bore, 1,2,3,4). If my memory serves, the rod numbers face the exhaust side of the block.

- I use assembly lube when putting an engine back together, although I've heard people using just a heavier oil or even something like STP. Assembly lube is preferred.

- On first start up, remove the plugs and rotate the engine by hand through a few complete rotations to make sure there are no clearance issues. Make sure the auxiliary shaft pulley is timed correctly. Before starting and with the plugs still removed, spin the engine a while with the starter motor until you see some pressure on the gauge. When you verify that, reinstall the plugs and fire up that bad boy.

- After a few hundred miles on the engine, change the oil and retorque the head bolts. Check all bolts for tightness, especially the exhaust manifold bolts/nuts as they can loosen with a few heat/cool cycles.

- Don't forget to add coolant. Yes, I did this once but remembered before anything bad happened.

-Bryan

18Fiatsandcounting wrote:Before starting and with the plugs still removed, spin the engine a while with the starter motor until you see some pressure on the gauge.

That was oil pressure that I was referring to. Typing too fast.

More updates!

Thank you Bryan for you input!!!
1. Thrust washer, that one i managed to get right myself. Yay!! The grooves are facing the crank and NOT the block.
2. The main bearing cap order, i did mess up! So thank for pointing that out! Some caps only can have 1 possible location. For example there is a cap with a small bolt. Also cap for cylinder #4 is much wider than the rest to keep the thrust washers in place (i think). caps 1, 2 and 3 can possible go in any of those slots, i'm glad to learn that there is a specific place for them. I found this video by ELDEST Builds (starting at 12:57) for a reference. https://youtu.be/HC43josnpak?t=777
See below the correct crankshaft main bearing orientation and placement.
3. I used engine oil on the crankshaft <> bearing surface and assembly lube on the other parts.
4-6. Will follow once i get to that point

I do have a question about pistons and piston orientation. There is an arrow on top of the new pistons, what is that for? if there is no specific orientation for them, i'll match them it from the old pistons. Pics below for reference.